Method of Transmitting a Data Block in a Wireless Communication System

1. A method of transmitting a data block in a user equipment of a wireless communication system, the method comprising: receiving upper layer data through at least one upper layer channel established in the user equipment; generating a data block including at least a part of the upper layer data, at least one channel indicator indicating each of the at least one upper layer channel, and information associated with a transmission buffer status of the at least one upper layer channel, wherein the information associated with the transmission buffer status indicates whether a prioritized bit rate (PBR) established in the user equipment is satisfied; and transferring the generated data block to a lower layer, wherein the PBR is defined by an amount of minimum data guaranteed to be transmitted through each of the at least one upper layer channel, and wherein the user equipment determines the information associated with the transmission buffer status by using user data of the upper layer data excluding at least one upper layer header included in the upper layer data.

2. The method of claim 1 , wherein the PBR is previously set per the at least one upper layer channel established in the user equipment.

3. The method of claim 1 , wherein the information associated with the transmission buffer status is included per each logical channel of the generated data block.

4. The method of claim 1 , wherein the information associated with the transmission buffer status is included per each logical channel group of the generated data block.

5. The method of claim 1 , wherein the information associated with the transmission buffer status is included per each radio bearer or radio bearer group in the generated data block.